On Wed, Oct 09, 2019 at 01:31:34PM +0200, Christian Brauner wrote: > When assiging and testing taskstats in taskstats_exit() there's a race > when writing and reading sig->stats when a thread-group with more than > one thread exits: > > cpu0: > thread catches fatal signal and whole thread-group gets taken down > do_exit() > do_group_exit() > taskstats_exit() > taskstats_tgid_alloc() > The tasks reads sig->stats without holding sighand lock seeing garbage. > > cpu1: > task calls exit_group() > do_exit() > do_group_exit() > taskstats_exit() > taskstats_tgid_alloc() > The task takes sighand lock and assigns new stats to sig->stats. > > Fix this by using smp_load_acquire() and smp_store_release(). > > Reported-by: [email protected] > Fixes: 34ec12349c8a ("taskstats: cleanup ->signal->stats allocation") > Cc: [email protected] > Signed-off-by: Christian Brauner <[email protected]> > Reviewed-by: Dmitry Vyukov <[email protected]>
_sigh_, let me resend since i fcked this one up. Christian
